# Questions tagged [soi]

Questions regarding the Sphere Of Influence, a region around a celestial body where it is the primary gravitational influence on orbiting objects.

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### Is there an established name for the regions "above" or "below" the ecliptic plane in our Solar System?

In our Solar system, all of the planets orbit the Sun along a plane known as the ecliptic. If we extend the ecliptic plane into a sphere of the same radius centred around our Sun, is there any ...
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### How to choose the best direction to leave Earth's sphere of influence?

What direction is optimal for spacecraft to leave Earth's sphere of influence (SOI) when it's going to an outer or inner planet? Let's presume that we have a spacecraft in a circular LEO (ecc=0.0). ...
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### Has any human ever had the choice to leave Earth permanently?

Far beneath the ship / The world is mourning They don't realize / He's alive No one understands But Major Tom sees / "Now the light commands This is my home / I'm coming home." Peter ...
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### From which direction should a spacecraft intercept a target planet's sphere of influence for an inner-to-outer planet trajectory?

Suppose a spacecraft is on an interplanetary Hohmann transfer trajectory from an inner planet to an outer planet. When the spacecraft finally enters the target planet's sphere of influence, which ...
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### How can I find the time of flight between spheres of influence?

I'm simulating an interplanetary trajectory between two spheres of influence. I have already simulated a hyperbolic escape within the sphere of influence and have arrived at the boundary of the ...
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1 vote
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### How to calculate the sphere of influence radius of the sun and other stars?

I am creating a space exploration game and I'm gathering formulas for determining how the player's spacecraft will act in space. One thing I need to know is how to calculate how far a spacecraft can ...
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### If there was a probe orbiting at the edge of Earth's Sphere of influence, how slow would it orbit?

Would it orbit very slowly? It's kinda been stuck in my head lately...
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### Mars Orbit Upon Intercept

I'm running a numerical simulation that calculates an interplanetary trajectory from Earth to Mars, and I'm trying to get a spacecraft into an orbit about Mars upon intercept, but am having a little ...
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### How do orbital elements change when force is applied orthogonal to the velocity vector?

Let's say you are standing on the Moon, with the Earth directly above your head (the moon being tidally locked with the earth. At this point you and the Moon are sharing an orbit, both experiencing ...
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### Why is the SOI of Jupiter less than that of Neptune?

Recently we had a question on gravitational SOI (Sphere of Influence) of planets but the image in answer has a plot showing that the SOI of Jupiter is less than that of Neptune. However, Jupiter's ...
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